From c339accedcfe2348d30d6efb8a83d0f06d191bbf Mon Sep 17 00:00:00 2001
From: Quinn <quinnthepigeon@proton.me>
Date: Mon, 8 Sep 2025 12:51:24 +0200
Subject: [PATCH] rework clear rows function to be more efficient, and shorter.

---
 src/game/tetromino/placing.c | 53 ++++++++++--------------------------
 1 file changed, 15 insertions(+), 38 deletions(-)

diff --git a/src/game/tetromino/placing.c b/src/game/tetromino/placing.c
index c1d1c89..a9d7dd0 100644
--- a/src/game/tetromino/placing.c
+++ b/src/game/tetromino/placing.c
@@ -12,47 +12,24 @@
 #include "shapes.h"
 
 
-/* count the empty columns in the row */
-__attribute_const__ static int count_empty(u8 const* restrict row) {
-	int cnt = 0;
-#if defined(__clang__)
-#pragma unroll COLUMNS
-#elif defined(__GNUC__)
-#pragma GCC unroll COLUMNS
-#endif
-	for (int i = 0; i < COLUMNS; i++)
-		cnt += !row[i];
-	return cnt;
-}
+static int clear_rows(u8* restrict* restrict rows) {
+	int count = 0;
+	u8* cache[4]; /* the maximum amount of rows the user can clear at once is four */
 
-/* checks for filled rows, clearing a max of 4 consecutive rows, if present.
- * all row pointers will be moved down to fill the gap, the filled rows will be inserted at the top, and zeroed-out */
-static void clear_rows(u8* restrict* restrict rows, u16* const score) {
-	u8* cache[4] = {0}; // the I piece is 4 long, meaning only 4 rows can be cleared at a time
-	uint fillc = 0;
-	uint checkc = 0;
+	for (int y = ROWS - 1; y >= 0; y--) {
+		int x = 0;
+		while (x < COLUMNS && rows[y][x] && count < 4) x++;
+		if (x >= COLUMNS) cache[count++] = rows[y];
+		else rows[y + count] = rows[y];
+	}
 
-	for (uint y = 0; y < (ROWS - fillc) && checkc <= 4; y++) {
-		int i = (ROWS - 1) - y;    // invert the index direction, so we start at the highest index
-		rows[i] = rows[i - fillc]; // either assigns the current row to itself, or to the "next" row
-
-		if (count_empty(rows[i])) {
-			checkc += (fillc > 0 && checkc < 4);
-			continue;
+	if (count) {
+		for (int i = 0; i < count; i++) {
+			memset(cache[i], 0, COLUMNS);
+			rows[i] = cache[i];
 		}
-
-
-		cache[fillc] = rows[i]; // cache the current row address, since it's going to be overridden
-		fillc++;
-		checkc++;
-		y--;
-	}
-
-	*score += (8 << fillc) * !!fillc;
-	for (uint i = 0; i < fillc; i++) {
-		memset(cache[i], 0, COLUMNS);
-		rows[i] = cache[i];
 	}
+	return count;
 }
 
 /* writes a shape to the screen */
@@ -99,7 +76,7 @@ int place_update(struct gamedata* gdat, int movdat) {
 	if (tmp) {
 		gdat->pdat.sel[VY]--;
 		plcmnt_place(gdat->rows, id, gdat->pdat.sel);
-		clear_rows(gdat->rows, &gdat->pnts); // clear the rows that have been completed
+		gdat->pnts += clear_rows(gdat->rows) << 4; // clear the rows that have been completed
 		next_shape();
 		audio_play(AUDIO_ID_PLACE);